Field of the Invention
The present invention relates to a detection apparatus, a detection system, and a method for producing a detection apparatus that are applied to a medical image diagnostic apparatus, a nondestructive inspection apparatus, an analysis apparatus using radiation, or the like.
Description of the Related Art
In recent years, thin-film semiconductor production techniques have been applied to the fabrication of radiation detection apparatuses which include an array of pixels (a pixel array). In these apparatuses, each of the pixels is provided by combining a switching element, such as a thin film transistor (TFT), and a conversion element, such as a photodiode, that converts radiation or light into electric charge. A detection apparatus of the related art described in Japanese Patent Laid-Open No. 2007-035773 includes conversion elements provided on electrodes that are disposed on a substrate. The electrodes are composed of a transparent conductive oxide, and are separated from one another on a pixel-by-pixel basis. Furthermore, the detection apparatus of the related art further includes switching elements that are connected to the electrodes via contact holes provided in an interlayer insulating layer. The interlayer insulating layer is disposed between the substrate and the electrodes, and is composed of an organic material. The conversion elements of the detection apparatus of the related art are separated from one another on a pixel-by-pixel basis in such a manner that an impurity semiconductor layer and a semiconductor layer thereof are removed on the interlayer insulating layer. However, in the production of a structure described in Japanese Patent Laid-Open No. 2007-035773, in the case of depositing an impurity semiconductor film, which is to be the impurity semiconductor layer of the conversion elements, and a semiconductor film, which is to be the semiconductor layer of the conversion elements, and in the case of removing the impurity semiconductor film and the semiconductor film on the interlayer insulating layer, a process in which the interlayer insulating layer is exposed is present. More specifically, on the substrate, a region in which no pixel is disposed (a pixel-array outside region) is present outside a region in which multiple pixels are disposed (a pixel-array region). In order to make the thickness of the interlayer insulating layer uniform in the pixel-array region, the interlayer insulating layer is not only disposed within the pixel-array region, but also disposed so as to extend beyond the pixel-array region and reach the pixel-array outside region. Thus, in the case of forming the conversion elements, the exposed area of the interlayer insulating layer in the pixel-array outside region is larger than that of the interlayer insulating layer in the pixel-array region. When the interlayer insulating layer, which is composed of an organic material, is exposed in the case of forming the conversion elements using a chemical vapor deposition (CVD) method, an etching method, or the like, organic contamination in which the organic material is mixed into the conversion elements can occur. A large difference between the exposed areas of the interlayer insulating layer leads to a large difference between the degrees of organic contamination. Thus, there can be a large difference between the degree of organic contamination of the conversion elements located at the edges of the pixel-array region and the degree of organic contamination of the conversion elements located at the center of the pixel-array region. For this reason, the difference between the degrees of organic contamination leads to a large difference between the conversion characteristics of the conversion elements located at the edges of the pixel-array region and the conversion characteristics of the conversion elements located at the center of the pixel-array region. Therefore, the difference in conversion characteristics of the conversion elements located at the edges of the pixel-array region as compared to the conversion characteristics of the conversion elements located at the center of the pixel-array region can cause an image artifact to occur during imaging.